High energy pulse switch in which a spiral magnetic field is established around each power electrode



Sept. 29, 1970 w. B. HU ABAY 3,531,683 HIGH ENE PULSE SWITCH I HI A SPIRAL MAG E IC FIELD IS STABLISHED AROU E POWER ELECT Filed Aug. 1968 POWER GOA/700A SU/J/JLY VOLTAGE :E I i I 5 INVENTOR. WALL/AM 5. HUC/(ABAY United States Patent HIGH ENERGY PULSE SWITCH IN WHICH A SPIRAL MAGNETIC FIELD IS ESTABLISHED AROUND EACH POWER ELECTRODE William B. Huckabay, 4225 Greenbrier,

Dallas, Tex. 75225 Filed Aug. 27, 1968, Ser. No. 755,624 Int. Cl. H011 7/44, 13/46 U.S. Cl. 315-36 Claims ABSTRACT OF THE DISCLOSURE An improved high energy pulse switch wherein the power electrodes are supported in a spaced, crossing relation to each other and the trigger electrode is located below said cross point, thus when power is transferred between the power electrodes, a spiral magnetic field is established around each power electrode, forcing the resulting arc discharge up the length of the electrodes and dissipating the are off the ends of the power electrodes, thereby distributing the wear over the length of the power electrodes and providing a switch capable of performing separate switching functions in rapid succession.

BACKGROUND OF THE INVENTION Field of the invention This invention relates generally to improvements in energy switching devices, and more particularly, but not by way of limitation, to high energy pulse switches used to transfer relatively high energies to various types of loads in response to a given control signal.

Description of the prior art Prior devices used to perform the function of switching high energy have consisted of two power electrodes, disposed a distance apart and approximately'in line. Generally, these electrodes are fixed in position in such a manner that the distance between them is readily adjustable. One of the electrodes is connected to a power supply and the other electrode is connected to a load. The distance between the two eletcrodes is adjusted to a point just beyond which current will be conducted between them. At this point no energy can be transferred from the power supply to the load.

A third electrode, generally of smaller diameter, is placed in close proximity to one of the power electrodes. This third electrode is generally referred to as a trigger electrode. The trigger electrode is connected to a control voltage, which is generally of some value smaller than the power supply voltage.

All three electrodes are surrounded by a gas, which is commonly air, when used to switch high energies. When a pulse is applied to the trigger electrode from the control voltage source, there exists an electron flow between the,

trigger electrode and the nearest power electrode. This flow of electrons starts an ionization process in the surrounding gas. This process continues until an electrical path is provided between the two power electrodes and conduction between them can take place. At this point there is an arc discharge between the two power electrodes and the energy from the power supply is switched, or transferred to the load.

'Because of the high energies dissipated in the are dis charge, and the ionized condition of the surrounding gas, the voltage is frequently driven into the negative region resulting in an oscillation. This oscillation will decrease in value, as a function of time, and eventually dissipate. The result is an attenuated oscillation. However, because of this oscillatory effect, there exists a period of time in which a subsequent switching operation cannot be performed. Thus, the number of switching operations per minute is limited by the above described elfect; a sharp pulse cannot be obtained and the power supply is overloaded.

It is also apparent that, as a result of the transfer of V electrons and the high energy dissipated during the are discharge, the ends of the power electrodes will experience some wear. The ultimate effect of this wearing is to increase the distance between the power electrodes. When the distance is increased beyond a certain point, the trigger electrode can no longer function to initiate the arc discharge and the power electrodes must then be adjusted.

There are prior art devices which employ two trigger electrodes spaced a distance apart and generally on a plane perpendicular to the plane of the two power electrodes. Then, when the control voltage is applied to the trigger electrodes an electron flow exists between them, causing an ionization of the gas in this area, thus providing an electrical path between the power electrodes, producing an arc discharge similar to that previously described. As may be noted, the oscillatory effect and the wearing of the electrodes are still present in this design.

SUMMARY OF THE INVENTION The present invention contemplates a pulse switch for controlling the application of electrical energy from a power supply to a load and broadly comprises a pair of upwardly extending and horizontally spaced, elongated power electrodes supported in crossing relation. The lower end of one of said power electrodes is adapted for connection with a power supply. The lower end of the other power electrode is adapted for connection with a load. The upper ends of the power electrodes are free. Between the power electrodes is an elongated trigger electrode extending upwardly with the upper end thereof terminating below the upper ends of the power electrodes.

A pulse from a control voltage source to the trigger electrode will selectively ionize a portion of the gas between the power electrodes and initiate an arc discharge, or, in other words, a transfer of energy between the power electrodes. When the arc discharge occurs between the power electrodes a spiral magnetic field is established around each of the power electrodes. This field will exert a force, causing the arc to travel up the length of the power electrodes and ultimately to be dissipated off the ends of the two power electrodes.

One effect of an arc traveling up the length of the power electrodes is to distribute the wearing of the power electrodes along the lengths of the power electrodes, rather than concentrating the wear at the end points of the power electrodes. Thus, the space relation of the power electrodes is maintained, eliminating the need for continuous adjustment to compensate for the wearing. Because the relationship is maintained, the voltage range rating for a given switch may be increased.

Also, since the are discharge travels up the lengths of the power electrodes, and is dissipated olf the ends of the power electrodes, stability is maintained between the trigger electrode and the power electrodes. Therefore, it is possible, using the present invention, to perform the switching function in rapid succession.

An object of the invention is to increase the efficiency of pulse switches.

Another object of the invention is to provide a pulse switch with a broader range of operating voltages.

A further object of the invention is to provide a pulse switch capable of performing separate switching functions in rapid succession.

A still further object of the invention is to provide a pulse switch which is economical in construction and operation and wherein the continuous adjustment of the electrodes to compensate for wear is eliminated.

Other objects and advantages of the invention will be evident from the following detailed description when read in conjunction with the accompanying drawings which illustrate various embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic front view, partially in cross section, of one embodiment of my invention.

FIG. 2 is a view taken along lines 22 of FIG. 1.

FIG. 3 is a top view of the embodiment of the invention shown in FIG. 1.

FIG. 4 is a schematic showing of one form of external circuitry which may be used employing the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in FIG. 1, this embodiment of the pulse switch comprises an enclosure 12 of an electrical insulative material which has a base 14 and sidewalls 16 and 18 thereon. The space 20 between the side walls 16 and 18 contains a gas. When the present invention is used as an open air pulse switch, the gas mentioned, is of course, air.

Three electrodes 22, 24 and 26 are extended through the base 14 into the space 20. As viewed in FIG. 1, the three electrodes lie in separate planes, which are approximately parallel. The electrodes 22 and 26 are the main or power electrodes, and the third electrode 24 is commonly referred to as the trigger electrode. The electrodes 22, 24 and 26 are constructed of an electrically conductive material, such as tungsten. The electrodes are typically formed from a rod of such material, the diameter of which depends on the power rating of the switch. A switch of a 10,000 volt rating would employ approximately a A; inch diameter rod to form electrodes 22 and 26, and approximately a inch diameter rod to form the trigger electrode 24.

The end points 28 and 30 of power electrodes 22 and 26 lie in a plane which is slightly below the plane formed by the upper ends 32 and 34 of sidewalls 16 and 18. The end point 36 of the trigger electrode 24 is below the plane formed by the end points 28 and 30, and will be more specifically located hereinafter.

The electrodes 22 and 26 are supported in substantially parellel relation and are laterally spaced apart by a distance 38. This distance 38 is determined by the particular voltage rating of the switch and is sufiiciently large to prevent arcing between the power electrodes 22 and 26. In a switch with a voltage rating of 10,000 volts, the distance ,38 would be adjusted or constructed to be approximately 4 inch.

The trigger electrode 24 is supported between the two parallel planes formed by electrodes 22 and 26 and is preferably located half way between the' power electrodes, but may be disposed slightly closer to one of the power electrodes.

Referring to FIG. 2, the space relationship of the three electrodes may be more fully described. The power electrode 22, in penetrating surface 40 of base 14, forms an acute angle 42 with said surface. The power electrode 26, in penetrating surface 40, forms an obtuse angle 44 with said surface. The angles thus formed by the said two electrodes are approximately supplementary. Viewed from one side, the surfaces of the power electrodes 22 and 26 nearest the trigger electrode 24 form lines which are shown in FIG. 2 to intersect at point 46. The power electrodes are so disposed that the said intersection 46 occurs above the surface 40. The trigger electrode 24 extends above surface 40, preferably terminating at a position where its end point 36 is below the intersection 46 of power electrodes 22 and 26.

The various planes and space relationships referred to above may be made more clear by referring to FIG. 3 which is a top view of the switch 10.

FIG. 4 is a typical schematic drawing illustrating one external circuit arrangement which may be employed using the pulse switch 10. The power electrode 26 is connected to a given load 50, such as the power source of a marine geophysical prospecting apparatus. The power electrode 22 is connected to a capacitor 52 and a power supply 54 in parallel. The value of capacitor 52 depends on the rating of the power supply, and for a 10,000 volt rated power supply the capacitor would be approximately 400 microfarads. The energy stored in capacitor 52 will build up to a certain valve in relation to the power supply voltage. The capacitor 52 will tend to discharge through the electrode 22, however, because of the distance between power electrodes 22 and 26, no power will be transferred between the power electrodes until the switch 10 is triggered, as will be described.

The trigger electrode 24 is conected through a capacitor 56 in parallel with a resistor 58 to a control voltage source 60. The control voltage source 60 will, upon a given response, have an output pulse of a given voltage value. The output pulse will be fed to the trigger electrode 24 through the capacitor 56. Resistor 58 is provided to drain any excess current produced in the circuit when the switch is not operating, and thereby prevent any charge build up in capacitor 56 during this non-operate time. The control voltage source 60 is typically rated at 5,000 volts when the power supply 54 is rated at 10,000 volts. Assuming this value for the control voltage source, the values of the capacitor 56 and resistor 58 are typically 500 microfarads and 20 megaohms, respectively.

The voltage pulse received by the trigger electrode 24 will cause an electron fiow to be established between the trigger electrode 24 and either power electrode 22 or 26. In order for the device to be effective with a reasonable voltage applied to the trigger electrode 24, the trigger electrode 24 must be spaced from one of the power electrodes a distance less than one-half the minimum distance between the power electrodes. Further, the distance between the trigger electrode and the other power elecrode must be less than the minimum distance between the power electrodes in order that arcing will occur between the power electrodes when arcing occurs between the trigger electrode and one of the power electrodes, and the operating range of the switch is increased when the trigger electrode is moved toward the half-way point between the power electrodes.

Equal value resistors 62 and 64 are provided between the trigger electrode 24 and the power electrodes 22 and 26 to balance the potential between the electrodes, thereby effectively maintaining an essentially constant potential difference between each of the power electrodes 22 and 26 and the trigger electrode 24. This balance will control the point of initial arcing to be between the trigger eletcrode 24 and the nearest power electrode 22 or 26. The ohmic value of resistors 62 and 64 is typically 20 megaohms when the power supply 54 rating is 10,000 volts.

The electron flow, previously mentioned, which is established between the trigger electrode 24 and one of the power electrodes 22 or 26 when the control voltage pulse is applied to the said trigger electrode, will result in an ionization of the gas between the trigger electrode and the closest power electrode, thus decreasing the resistance between the two power electrodes 22 and 26. The breakdown of the surrounding gas, and the presence of the conducting path, permit the capacitor 52 to discharge, resulting in an arc discharge between the two power electrodes. This are discharge transfers the power stored in the capacitor 52 to the load 50.

This transfer of power between the electrodes 22 and 26, and the space relationship between the electrodes 22 and 26, causes a spiral magnetic field to be established about each power electrode. This spiral magnetic field will force the arc discharge to travel up the lengths of the power electrodes 22 and 26 and be dissipated off the ends 28 and 30 of the power electrodes 22 and 26 respectively. The eflect of forcing the arc discharge up the lengths of the power electrodes, and providing a complete dissipation of the are off the ends of the power electrodes, is to provide a more stable condition in the surrounding gas and eliminate the opportunity for the are back, or the oscillatory effect previously mentioned.

With the oscillatory eifect eliminated, the switch is immediately acapble of receiving a subsequent control pulse and again transferring the energy to the load. Thus, it is apparent that the present invention provides a pulse switch capable of performing the switching function in rapid succession wtihout the delay time usually encountered in high energy pulse switches.

Since the arc discharge is not concentrated on the ends of the power electrodes, the wearing of the electrodes is decreased and distributed, allowing the distances between the electrodes to be maintained to a closer tolerance, without requiring periodic manual adjustment. The distribution of the wearing of the electrodes indicates one reason that the end 36 of trigger electrode 24 is located below the cross point 46 of the two power electrodes 22 and 26. If the end 36 were located above this point, the trigger electrode 24 would be in close proximity to the power electrodes at two different points, one below the cross point 46 and one above said cross point 46, resulting in the arc discharge periodically occurring above the cross point 46 and, thus, concentrating the wearing of the electrodes over a smaller area. Because the distances between the electrodes are not subject to the distance variance previously described, a given pulse switch, constructed in accordance with the present invention, is operable over a wider range of voltages.

It is apparent that, although, the foregoing discussion describes a pulse switch for use as an open air switch, the electrodes 24, 22, and 26 could be encapsulated in an enclosure of glass or other appropriate material. The enclosure could be gas filled, and either under a pressure or a vacuum, as dictated by the particular application. The principles of such encapsulation are well known in the industry and require no further explanation.

Changes may be made in the construction and arrangement of parts or elements of the various embodiments as disclosed herein without departing from the spirit and scope of the invention as defined in the following claims. In the claims, the terms, upwardly, downwardly and horizontally are used solely for ease of verbal orientation, it being understood that the various electrodes could be extended in other directions, as long as the expressed relations are maintained.

What is claimed is:

1. A switch for controlling the application of electrical energy from a power supply to a load, comprising:

a pair of upwardly extending and horizontally spaced,

elongated power electrodes supported in crossing relation, the lower end of one of said power electrodes being adapted for connection with the power supply, the lower end of the other power electrode being adapted for connection with the load, and the upper ends of said electrodes being free; and

an elongated trigger electrode extending upwardly between the power electrodes with the upper end thereof terminating below the upper ends of the power electrodes for selectively ionizing a portion of the gas between the power electrodes and initiating the transfer of energy between the power electrodes.

2. The switch of claim 1 wherein the power electrodes lie in parallel planes.

3. The switch of claim 1 characterized further to include an electrical insulative means surrounding the lower end portion of each of said power electrodes and the lower end portion of said trigger electrode.

4. The switch of claim 1 wherein said upper ends of the power electrodes extend upwardly to approximately the same height.

5. The switch of claim 2 wherein the trigger electrode lies in a plane parallel to said planes of the power electrodes.

6. The switch of claim 1 wherein the trigger electrode is disposed relatively closer to one of said pair of power electrodes.

7. The switch of claim 1 wherein the upper end of the trigger electrode terminates below said crossing point of the pair of power electrodes.

8. The switch of claim 1 wherein the trigger electrode is of a smaller diameter than the diameters of the power electrodes.

9. The switch of claim 1 characterized further to include:

a power supply source connected to one of said pair of power electrodes;

an electrical load means connected to the other of said pair of power electrodes;

a control voltage supply means connected to said trigger electrode; and

a resistor connected between each of the power electrodes and the trigger electrode.

10. The switch of claim 9 wherein said resistors are of equal value.

References Cited UNITED STATES PATENTS 2,230,727 2/ 1941 Partington 313-325 2,997,623 8/1961 Westendorp 315-56 3,159,765 12/1964 Schultz et al. 315-36 3,230,411 l/1966 Smith 313-306 X 3,292,049 12/1966 Lucas 315-35 X 3,312,868 4/1967 Vodicka 315-36 X 3,450,946 6/1969 Camacho 315-36 X 3,454,823 7/1969 Marx et a1. 315-36 JOHN W. HUCKERT, Primary Examiner A. J. JAMES, Assistant Examiner U.S. Cl. X.R. 313-306, 308, 325; 317-61 

